View source for 1szo


==Crystal Structure Analysis of the 6-Oxo Camphor Hydrolase His122Ala Mutant Bound to Its Natural Product (2S,4S)-alpha-Campholinic Acid==
<StructureSection load='1szo' size='340' side='right'caption='[[1szo]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1szo]] is a 12 chain structure with sequence from [https://en.wikipedia.org/wiki/Rhodococcus_sp._NCIMB_9784 Rhodococcus sp. NCIMB 9784]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SZO OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1SZO FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.9&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CAX:(2S,4S)-4-(2,2-DIHYDROXYETHYL)-2,3,3-TRIMETHYLCYCLOPENTANONE'>CAX</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1szo FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1szo OCA], [https://pdbe.org/1szo PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1szo RCSB], [https://www.ebi.ac.uk/pdbsum/1szo PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1szo ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CAMK_RHOSO CAMK_RHOSO] Catalyzes the carbon-carbon bond cleavage of the bicyclic beta-diketone 6-oxocamphor via a retro-Claisen reaction to yield the optically active (2R,4S)-beta-campholinic acid. It is also able to cleave 2,2-disubstituted cyclohexa-1,3-diones such as 2-methyl-2-propylcyclohexa-1,3-dione and 2-methyl-2-butylcyclohexa-1,3-dione which result in racemic keto acid products. Transformations of the bicyclic diketone substrates bicyclo[2.2.1]heptane 2,6-dione and bicyclo[2.2.2]octane-2,6-dione yield (S)-keto acid products.<ref>PMID:11278926</ref> <ref>PMID:15138275</ref> 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/sz/1szo_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1szo ConSurf].
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== Publication Abstract from PubMed ==
The crotonase homolog, 6-oxo camphor hydrolase (OCH), catalyzes the desymmetrization of bicyclic beta-diketones to optically active keto acids via an enzymatic retro-Claisen reaction, resulting in the cleavage of a carbon-carbon bond. We have previously reported the structure of OCH (Whittingham, J. L., Turkenburg, J. P., Verma, C. S., Walsh, M. A., and Grogan, G. (2003) J. Biol. Chem. 278, 1744-1750), which suggested the involvement of five residues, His-45, His-122, His-145, Asp-154, and Glu-244, in catalysis. Here we report mutation studies on OCH that reveal that H145A and D154N mutants of OCH have greatly reduced values of k(cat)/K(m) derived from a very large increase in K(m) for the native substrate, 6-oxo camphor. In addition, H122A has a greatly reduced value of k(cat), and its K(m) is five times that of the wild-type. The location of the active site is confirmed by the 1.9-A structure of the H122A mutant of OCH complexed with the minor diastereoisomer of (2S,4S)-alpha-campholinic acid, the natural product of the enzyme. This shows the pendant acetate of the product hydrogen bonded to a His-145/Asp-154 dyad and the endocyclic carbonyl of the cyclopentane ring hydrogen bonded to Trp-40. The results are suggestive of a base-catalyzed mechanism of C-C bond cleavage and provide clues to the origin of prochiral selectivity by the enzyme and to the recruitment of the crotonase fold for alternate modes of transition state stabilization to those described for other crotonase superfamily members.

Structure of 6-oxo camphor hydrolase H122A mutant bound to its natural product, (2S,4S)-alpha-campholinic acid: mutant structure suggests an atypical mode of transition state binding for a crotonase homolog.,Leonard PM, Grogan G J Biol Chem. 2004 Jul 23;279(30):31312-7. Epub 2004 May 11. PMID:15138275<ref>PMID:15138275</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Rhodococcus sp. NCIMB 9784]]
[[Category: Grogan G]]
[[Category: Leonard PM]]